Impulse transmitter for automatic telephone systems



March 13, 1928. 1,662,141

N. BLADES ET AL IMPULSE TRANSMITTER FOR AUTOMATIC TELEPHONE SYSTEMS Filed March 1927 Patented Mar. 13, 1928.

UNITED STATES,

PATENT OFFICE.

NEWTON BLADES AND LEONARD VICTOR'MARKS, OF LONDON, ENGLAND, ASSIGNORS TO THE STERLING TELEPHONE & ELECTRIC COMPANY LIMITED, 01 LONDON, ENG- LAND, A COMPANY OF GREAT BRITAIN AND IRELAND.

IMPULSE TRANSMITTER FOR AUTOMATIC TELEPHONE S YSTEMS.

Application filed March 1, 1927, Seria1No. 171,894, and in Great Britain March 15, 1926.

This invention relates to impulse trans mitters for use in automatic telephones for sending to an exchange groups of impulses corresponding to the digits to Which the transmitter is successively set by a subscriber.

The purpose of the invention is the production of an impulse transmitter by which the whole dialling operation shall be expeditiously carried out, but which it shall be beyond the power of the subscriber to accelerate or interfere with.

vTo this end the invention comprises an impulse transmitter in which the movement of the finger plate operated by the sub scriber is wholly independent of the impulse sending operation, said finger plate being set by the subscriber as rapidly as he pleases, and returning or being returned without affecting the impulse sender, and being rendered powerless to actuate the impulse sender further until the impulse sending operation determined by its last forward movement is completed.

In a preferred construction of the invention the impulse sender comprises a preferably spring actuated driver and an impulse mechanism which is operated by the driver during its return to the position of rest under the action of its spring, the operation being controlled by a governor; the driver is carried forward by the finger plate during forward movement of the latter, but the finger plate returns independently of the driver under the action of a separate spring. In the position of rest the finger plate is locked by a spring catch which is released by the impulse sender on completion of the impulse sending. To ensure proper engagement of the catch means are provided for slowing down the finger plate as it nears the position of rest.

This embodiment of the invention is illustrated in the accompanying drawings,

Figure 1 being a face view with part of the finger plate and cover broken away.

Figure 2 an edge View in median section.

Figure 3 a diagram illustrating the look ing notion.

Figure 4 a detail.

The finger plate A is secured upon a hub B rotating in a bearing C in the casing D. Within the casing there is attached to the hub a return spring L fastened to the casing, and at its end the hub carries an arm The end of this arm lies in the path of the end of a second arm G carried on a spindle F coaxial with the finger plate hub B. This spindle may carry the usual pawl (not shown) engaging (during return movement) the ratchet wheel K of the impulse sending mechanism 0, or may be associated with that mechanism to drive it in any usual fashion. The arm G and the pawl together with a spring (not shown) which tends always to return them to initial position constitute the driver. On rotation by the subscriber the linger plate A sets the driver so determining the number of impulses which will be sent, and on release returns, under the action of its spring L, faster than the driver G can return since the latter must carry with it the governor controlled impulse mechanism. If the return of the finger plate is accelerated by the subscriber the driver and impulse mechanism are not thereby affected.

As there is a possibility of the subscriber beginning the dialling of a further digit before the driver G has returned, a spring catch M bevelled on one side is rovided in the path of the arm E of the linger plate hub. The arm rides over this catch and is locked in its initial position between the catch and an abutment H as seen in Figure 3. The driver arm Gr upon its return also presses back the spring catch M but does not ride past it (Fig. 1). The ends of the arms E and Gr are flush with one another so that when the finger plate is again turned forward in contact with the driver arm it can pass the catch. To prevent a gap being Worn between the catch engaging surfaces of the finger plate arm and driver arm, the catch engaging surfaces of the driver arm instead of being flush with that of the finger plate arm may partly overlie it in the initial position.

To prevent the arm G striking the abutment H with suflicient force to rebound before the spring catch has engaged itthe end of the movement of the arm may be braked or cushioned in any suitable way. As shown inFigures 2 and 4 a leaf spring P is provided in the casin D which the arm E must depress to reacfi its initial position.

What we claim is 1. An impulse transmitter, comprising a driver, finger plate adapted to engage'and set said driver on forward movement and otherwise Wholly independent of it, means for returning said linger plate independently or said driver, means for returning said driver, an impulse mechanism operated by said driver in its return, and means rendering said finger plate inoperative until the return oi": the impulse sender is complete.

2. In an impulse transmitter the Combination with an impulse sender, oi a finger plate adapted on for aid movement to determine the extent of operation of said sender, a spring for returning said linger plate, a springeateli to engage said finger plate in the position of rest-until the 1mpnlse sendingis completed, andineans for. gradually arresting Saidiingerplate as it nears the position of rest. M

3. In an impulse transmitter the combi nation with an impulse sender, of aiinger plateadapted on "forward movement todetermlne the extent of operation of said sender, a spring for returning said finger plate, a' spring catch to engage said finger plate in the position of rest until the im pulse sending is completed, and a leaf 7 spring in the path of said finger plate adapted tohe deflected by it on nearing the position of rest.

4;. In an impulse transmitter the combination with an impulse sender operating during return to a position of rest, of a finger plateadapted to rotatesaid impulse sender forward and to return independently thereof, a spring catch, a member moving with said finger plate adapted to press back said catch and to be engaged thereby in the position of rest, and a member moving with said impulse transmitter also adapted to press back said catch, the catch engaging surfaces of said members overlapping in the resting position. V

In testimony whereof We have signed our names to this specification.

" NEl VTON BLADES.

LEONARD VfMARKS. 

